This encyclopaedia presents an extensive and integrated examination of groundwater hydrology and hydraulics, addressing scientific, engineering, planning, and management dimensions of subsurface water systems. It explains the physical, geological, and chemical processes governing groundwater occurrence, movement, and interaction with surface water systems. The discussion situates groundwater within the broader hydrologic cycle, emphasising system behaviour under natural variability and human-induced pressures. Analytical approaches to site characterisation, hydrogeological assessment, and water quality evaluation are explored alongside engineering and environmental considerations. The encyclopaedia also examines the implications of industrial development, land use, and climatic perturbations on groundwater resources. Policy frameworks, regulatory mechanisms, and governance challenges are analysed to demonstrate how scientific understanding informs sustainable management and equitable allocation. By integrating theory, applied methods, and policy perspectives, the work provides a coherent framework for understanding groundwater as a critical and finite resource within complex environmental and socio-economic systems.

It is intended for students, researchers, engineers, planners, and policy professionals in hydrology, hydrogeology, and water resources management. The encyclopaedia serves as an authoritative academic reference and practical guide for analysis, planning, and decision-making, supporting sustainable groundwater management across local, regional, and global contexts.